Combustion burners are used in the metal melting of iron and the like, in the manufacture of glass, in the incineration of waste, and the like. As methods that heat a target object such as metal, glass, waste, or the like, using a combustion burner, there are methods that heat by directly applying a flame to a target object, and there are methods that heat a target object indirectly using radiant heat of flame.
In comparison with methods that heat a target object indirectly using radiant heat of flame, methods that heat by directly applying flame to a target object have an advantage in that the efficiency of utilization of energy is high.
Patent Document No. 1 discloses melting a cold iron source using a combustion burner that heats by directly applying flame to the target object.
Given that, in a case in which a target object to be heated is a powder (a raw material powder), since the surface area per volume of the target object is large, it is possible to heat the target object with high efficiency by passing the target object through the flame and/or a high temperature region in the vicinity of the flame (hereinafter, referred to as a “flame region”).
Patent Document Nos. 2 to 4 disclose combustion burners and burning methods that heat by installing a powder-ejecting port, from which powder is ejected, in a combustion burner or in the vicinity of a combustion burner; and directly injecting the powder into the flame region while simultaneously ejecting the powder.
In the combustion burners that are disclosed in Patent Document Nos. 2 to 5, the powder-ejecting port is disposed in the center of the combustion burner, or in the vicinity thereof (hereinafter, referred to as “a central part of the combustion burner”).
However, powder has a property in which dispersal is difficult since there is no Brownian motion, and therefore, there is a tendency for uneven distribution.
In a case in which powder, which passes through a flame region of a combustion burner, is unevenly distributed, a situation in which the powder is not sufficiently heated in portions in which the density of the powder is high, and conversely, in which the heat of the flame is not utilized sufficiently in portions in which the density of the powder is low, arises. Therefore, the efficiency of utilization of the energy of the combustion burners is reduced.
In such an instance, in a case in which powder is heated using a combustion burner, it is necessary to disperse the powder and pass the powder through a flame region.
However, in the combustion burners that are disclosed in Patent Document Nos. 2 to 4, since the ejecting ports of powder are disposed in the central part of the combustion burner, the powder is passed through the flame region in an unevenly distributed state. Therefore, it is difficult to heat the powder, and the methods are inefficient.
As a related art technique that is capable of solving this problem, there are multiple pipe structure combustion burners that are set to have configurations in which, rather than being disposed in a central part of the combustion burner, a plurality of powder-ejecting ports are disposed at a periphery, which is a position that is further on an outer side than the central part of the combustion burner and has the center of the combustion burner as the center thereof, and in which the periphery, on which the plurality of powder-ejecting ports are disposed, is interposed between a periphery on which a plurality of burnable gas ejecting ports, which eject burnable vapor, and a periphery on which a plurality of fuel gas ejecting ports, which eject fuel, are disposed (for example, refer to Patent Document Nos. 5 and 6).
By using the abovementioned multiple pipe structure combustion burners, since powder is spread out and ejected, it is possible to greatly improve the dispersibility of powder that passes through a flame region.